In a major upcoming speech, Prime Minister David Cameron is promising battered Britain a respite from years of immigration overload by a particularly hostile bunch of diverse foreigners. He says he will decrease legal immigration by a substantial number: "we would aim to reduce net migration to the levels we saw in the 1980s and 1990s" according to the text of the speech.

If Britain actually were to do such a thing, it would be revolutionary, something that would make unhappy citizens around the world demand similar restrictions from their own governments.

In his most forthright speech on the issue since he became Prime Minister, he will say that mass immigration has led to "discomfort and disjointedness" in neighbourhoods because some migrants have been unwilling to integrate or learn English.

Pledging to cut the numbers entering Britain to tens of thousands, rather than hundreds of thousands, Mr Cameron will say that "for too long, immigration has been too high".

He will also promise to "stamp out" forced marriages, saying that "cultural sensitivity" cannot be allowed to stop the Government from acting.

In the speech to party members in Hampshire, the Prime Minister will attack Labour for claiming it was racist to talk about immigration, saying it is "untruthful and unfair" not to speak about the issue, however uncomfortable.

The Prime Minister will also blame the welfare state for creating a generation of workshy Britons, leaving the jobs market open for migrants. Figures show that of the 2.5 million extra people in employment since 1997, three quarters were foreign-born workers.

But Mr Cameron will argue that it is not a case of "immigrants coming over here and taking our jobs" because some migrants have created wealth and jobs.

He will say that the "real issue" is "migrants are filling gaps in the labour market left wide open by a welfare system that for years has paid British people not to work".

"Put simply, we will never control immigration properly unless we tackle welfare dependency," Mr Cameron will say.

He will say that he can see why people have argued that "immigration will remain high because British people won't do the jobs migrant workers do", adding: "We have had persistently, eye-wateringly high numbers of British-born people stuck on welfare."

The speech comes three weeks before the local elections and is likely to be seen as an attempt to convince voters that the Conservatives are in touch with public opinion.

The Tories are fighting a large number of council seats in the North where immigration was one of the major issues at last year's general election - with Labour subsequently admitting they failed to address the concern in their heartlands.

Mr Cameron will say: "When there have been significant numbers of new people arriving in neighbourhoods, perhaps not able to speak the same language as those living there, on occasions not really wanting or even willing to integrate, that has created a kind of discomfort and disjointedness in some neighbourhoods.

"This has been the experience for many people in our country and I believe it is untruthful and unfair not to speak about it and address it."

He will attack the levels of immigration under Labour and commit to tackling the obvious "abuses of the system" that routinely happen, including sham and forced marriages.

Mr Cameron will say: "For a start, there are forced marriages taking place in our country and overseas as a means of gaining entry to the UK. This is the practice where some young British girls are bullied and threatened into marrying someone they don't want to.

"I've got no time for those who say this is a culturally relative issue - it is wrong, full stop, and we've got to stamp it out."

Between 1997 and 2009, 2.2 million more people came to live in Britain than those who left to live abroad, Mr Cameron will say.

"That's the largest influx of people Britain has ever had and it has placed real pressures on communities. Not just pressures on schools, housing and health care - though those have been serious - but social pressures, too."

He will tell his audience that by getting to grips with all forms of immigration he can return it to the levels of the 1980s and 1990s.

"And I believe that will mean net migration to this country will be in the order of tens of thousands each year, not the hundreds of thousands every year that we have seen over the last decade," Mr Cameron will say.

It follows a speech by Mr Cameron earlier this year in which he said that British Muslims should subscribe to mainstream values of freedom and equality, and claimed that the doctrine of multi-culturalism had "failed".

Today, Mr Cameron will mount a vigorous defence of the Coalition's policies, saying they have started to bring immigration down.

He will single out those who have claimed that it was not possible to do so without harming the economy or British universities.

Vince Cable, the Business Secretary, fought a fierce Whitehall battle to try to ensure firms were not hampered by caps placed on immigrant workers and was vocal in his criticism of some of No 10's plans to limit entry into Britain.

Mr Cameron will outline the measures to ensure the best economic migrants can still be hired by companies, and will add: "I completely reject the idea that our new immigration rules will damage our economy."

He will reject concerns about the effect the tightening of rules on student visa applications will have on universities. He hopes to reduce the number of visas issued by 80,000 a year.

Figures yesterday showed a record number of foreign workers are based in Britain. There are almost four million migrants in work in this country despite government pledges to do more for British workers.

The number of people in employment increased by 212,000 during 2010, but more than 80 per cent was made up of migrants, according to the Office for National Statistics. Just over 29 million people were in work in Britain during the last quarter of 2010.

Of those, 3.89 million, or one in seven, were people born overseas, the highest level on record. That was a rise of 173,000 on the same period in 2009.

A Nobel prize-winning economist yesterday suggested ministers allow migrants to buy their way into the country.

Prof Gary Becker, of the University of Chicago, said selling visas for Â?30,000 a time would help the Government select the best migrants.